Question

For dissolution of $C{O}_2\left(g\right)$ in $H_{2}O\left(l\right)$
Which of the following statement is correct?

• A. Increase in temperature of the solution will decrease solubility of $C{O}_2$
• B. Increase in temperature of the solution will increase solubility of $C{O}_2$
• C. Increase in temperature of the solution will will have no effect on solubility of $C{O}_2$
• D. On increasing temperature of the solution , solubility of $C{O}_2$ first increases and then stays constant

Answer 1

The correct option is A Increase in temperature of the solution will decrease solubility of $C{O}_2$

Dissolution is a process where a solute in gaseous, liquid or solid phase dissolves in a solvent to form a solution. ​
It involves ​three steps:
Step 1: Involves the separation of solvent molecules ($\Delta H_1$)
Step 2: Separation of solute molecules ($\Delta H_2$)
Step 3: Solute and solvent molecules mix ($\Delta H_3$)
The heat of solution​,
$\Delta H_{solution}$ = $\Delta H_1$ + $\Delta H_2$ + $\Delta H_3$​

Effect of temperature on solubility will be based on the nature of dissolution.
If dissolution is an exothermic process, heat will be release when the solute and solvent get dissolved.

Dissolution of $C{O}_2$ in water is exothermic in nature.
According to Le- Chatelier's principle, when we increasing the temperature of this solution, to nullify its effect, the dissolution will go reverse and it will result in decrease in solubility of $C{O}_2$ in water. Similarly, decrease in temperature of the solution will increase the solubility of $C{O}_2$ in water.

When we heat the solution of carbonated water, the dissolved $C{O}_2$ will get evolved from the solution. This shows the less solubility of $C{O}_2$ in water at high temperature.

Thus, statement (a) is correct.